21138203 has 8 divisors (see below), whose sum is σ = 22725120. Its totient is φ = 19598760.

The previous prime is 21138179. The next prime is 21138209. The reversal of 21138203 is 30283112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21138203 - 2¹² = 21134107 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21138209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10943 + ... + 12728.

It is an arithmetic number, because the mean of its divisors is an integer number (2840640).

Almost surely, 2^21138203 is an apocalyptic number.

21138203 is a deficient number, since it is larger than the sum of its proper divisors (1586917).

21138203 is a wasteful number, since it uses less digits than its factorization.

21138203 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23737.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 21138203 is about 4597.6301504145. The cubic root of 21138203 is about 276.4963195492.

The spelling of 21138203 in words is "twenty-one million, one hundred thirty-eight thousand, two hundred three".